[BR289]

Some of that depends on what radio system and how many servos you are using and also what batteries. I use a Futaba 14MZ and dont need some of the features that are designed into the Powerbox. Some of the features in the Powerbox can be done through my radio. I am using a Powerbox Professional 40/24 in my Extreme Flight 110" Yak and and I have have a few Evolutions in other smaller planes.
I like them for some of the "Little" things such a led monitoring of my batteries, built in regulators, double signal amplifiers, and redundancy of the power system. If a servo "shorts" which can happen, It gets cut off at the Powerbox and no worries to the rest of the system. Thats piece of mind for me.
The Royal is a work of art! There isnt anything it doesnt do and if you have read the brochure on it I am sure you will agree. Its also the most expensive of the Powerbox line but well worth it in terms of protection and insurance.
My opinion though for your plane would be to get what you can afford. You never know what new plane you may decide to get next and whichever one you purchase can be used in your next project. I would think the Powerbox 40/24 Champion would be good. PowerBox makes lithium batteries in plastic cases that have a nice little mount. I am not sure if Duralite has them as they obviously have their own batteries but they are available through Aircraft International which is the Powerbox distributor and they can be seen at their website.
Hope that helps a little....
Blair